weird problem with accounts?

i'm having a weird problem with windows seven.

i've been using the administrator account on my boyfriend's computer as my account.

as of yesterday, when i select my account on the login screen, it logs me instead into a weird blank account with factory presets, without the files i've saved to my desktop or my preferences. on this account i'm apparently unable to uninstall programs or access user account management. it also seems to reset every time i restart the computer.

if i look in my computer, all my files are still present and accessible under the administrator account

what the hecky. can anyone help? i've never encountered this before. please ask if i've omitted any information!! thank you for your help!